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In this study, sequential feeding method was conducted due to some coal-fired power plants not being equipped by coal blending facility. Its effect on ash-related problem was investigated using drop tube furnace combustion test and ash particle observation method. AUS coal (low-slagging risk sample) and KT coal (high-slagging risk sample) were used to obtain AK-1 coal and AK-2 coal. AK-1 coal was a coal sample of out-furnace blending method, while AK-2 coal was coal sample of sequential feeding method. AK-1 probe tended to be more similar to AUS coal with only a small spot of ash attached on the probe surface. Meanwhile, AK-2 probe had more ash attached on the probe surface, indicating more severe slagging than AK-1 probe. According to ash morphology, the result indicated that the upper layer of slag tended to be more similar to AUS coal ash, while initial layer of slag of AK-2 coal contained more KT coal ash. Based on ash mineralogy, sodium in AK-2 coal was distributed evenly which was different with AK-1 coal. This result shows that sequential feeding method is not applicable to reduce slagging and fouling risk of KT coal. [ABSTRACT FROM AUTHOR]

A typical coal with high ash-melting -point from Huainan and Huaibei mining area (HN) and an Inner Mongolia coal with low ash・melting-point blended coal (ER) were selected and sieved into four distinct particle size ranges of > 150 pim, 75 〜150 |jim, 48 〜75 jjtm, and <48 |jim, respectively・ The mass ratio and ash yield in each particle size range were analyzed・ The ash chemical composition, minerals, and liquid phase formed during ash melting were determined by XRF, XRD, and thermodynamic equilibrium calculation, respectively・ The effect of particles size on the ash fusion temperature was investigated through mixing HN coal with ER coal with different particle size. The results indicated that the average ash particle size of HN coal increased with the increase of coal particle size, and the average ash particle size of ER coal was around 3 |jim when the particle size of ER coal was > 48 pirn; the ash yield of HN coal increased with the increase of coal particle size while the ER coal was opposite・ The ash chemical composition of the coal with different particle size was inhomogeneous・ The AFTs of HN coal increased with the increase of coal particles while the AFTs of ER coal decreased・ When HN coal blended with ER coal with different particle size, respectively, the ash fusion temperatures of the mixed coal was between them ・ When the HN coal (<48 pim) blended with the ER coal (> 150 jjim) in a mass ratio of 1 ♦ 1, high melting pointe mineral of mullite in ash was converted to low-melting point mineral of anorthite, resulting in the lowest FT of 1 317 °C. [ABSTRACT FROM AUTHOR]

Rising coal price and increasingly stringent emission policy highlight the importance of balancing economic benefit and sustainable development of coal-fired power plants. In order to make the power plant operate economically and safely, and reduce the emission of pollutants as much as possible, this paper proposed a coal blending optimization framework for coal-fired power plants. This framework constructs a set of mathematical model based on the minimization objective function, including the economy, safety and environmental protection of coal. And a multi-strategy fusion multi-objective particle swarm optimization (MSF-MOPSO) method is proposed to optimize the coal blending model. The feasibility, effectiveness and superiority of the method are theoretically verified by convergence analysis and several sets of simulation experiments. And the practical application of this framework shows that under the coal blending strategy based on different weight combinations, the algorithm proposed in this paper can produce high-quality Pareto spatial distribution. Comparing with other state-of-the-art coal blending algorithms, this method can reduce the coal purchase cost by 4.42% and ${\rm{S}}{{\rm{O}}_{\rm{2}}}$ S O 2 emission by 5.11% at least under the same condition. It has significant environmental protection and economic benefit. [ABSTRACT FROM AUTHOR]

To realize the high‐efficiency utilization of iron‐rich coal (ZC), it is necessary to conduct in‐depth research on its ash fusion characteristics and regulation mechanism. In this paper, the fusion temperature test of ZC coal ash was first carried out in a weak reducing atmosphere, and diatomite (GZT) and Naomaohu high‐calcium coal (NMH) were selected as additives. The results show that the four characteristic temperatures of ZC coal ash are all low under weak reducing conditions. The addition of NMH ash lowered the fusion temperature of ZC coal ash, while the GZT ash increased the fusion temperature to varying degrees. When the addition ratio of NMH ash is less than 40 %, the effect of increasing the difference between the deformation temperature and flow temperature of ZC coal ash is still positive. The addition of NMH ash made the slag system generate a high content of calcium‐magnesium feldspar and calcium‐iron feldspar, decreasing the fusion temperature of the blended coal ash. The addition of GZT ash increased the content of SiO2 in the slag system and promoted the increase of the iron‐pyroxene content, and the formation of the iron‐aluminum pyroxene and cordierite mineral phases, thereby increasing the coal ash fusion temperature. [ABSTRACT FROM AUTHOR]

High sulfur anthracite has high research value and application prospects in the preparation of carbon adsorbent due to its excellent coal quality conditions, but the pore structure changes and sulfur migration dynamics in the preparation process are not clear. In this paper, using SEM, pore structure analysis, Raman, FTIR and XPS, the feasibility of preparing carbon adsorbent from high-sulfur coal blending was analyzed from the perspective of apparent morphology, pore structure parameters, graphite crystal structure, and functional groups and content, while the occurrence form of sulfur in carbon adsorbent was explored. The results showed that the carbon adsorbent prepared from high-sulfur anthracite was mainly microporous, and the specific surface area was up to 1103.23 m2/g, which was the highest among the known high-sulfur coal materials. The degree of disorder of raw coal and the size of graphite crystal particles synergistically formed a rich pore structure. Sulfur in coal mainly exists in the form of thiophene and sulfide. An increase in the bituminous coal proportion promotes the transformation of carbon adsorbent to an alkaline environment. Thiophene sulfur is removed at 900°C, and sulfide is transformed into sulfoxide and sulfone under steam oxidation and Fe catalysis. [ABSTRACT FROM AUTHOR]

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Some ash related problems, such as slagging at furnace bottom and fouling at the air pre-heater surface, are frequently encountered during circulating fluidized bed gasification (CFBG) of Zhundong coal. Low ash fusion temperatures (AFTs) and intense sodium release should be responsible for those problems. In industry, coal blending is deemed to be a feasible method to both improve AFTs and control sodium release. In this work, Wuhai coal was selected as blending coal. The ratio is varied from 0% to 40% by mass with 10% interval. The mixed samples were gasified by steam at 950°C in a lab-scale furnace. Some key indices, such as sodium release behaviors, ash slagging characteristics and char gasification performances, were investigated by ICP-OES, AFTs, XRD and TG analyzers, respectively. The results indicated that coal blending could significantly decrease sodium release behaviors. For ash slagging characteristics, it is surprised to find that three out of four AFTs (deformation temperature, softening temperature, hemispherical temperature) show an U-shaped correlation with blending ratio, indicating that a low ratio possibly causes more severe ash slagging problem. It is ascribed to the formation of substantial percentage of fusible Na-containing silicates and aluminosilicates. In addition, coal blending greatly increases ST-DT, implying that the ability of resistance to bed temperature fluctuation is markedly enhanced. Due to the high level of alkali and alkaline species, the synergistic effect is clearly observed during co-gasification. Taking all key indices into consideration, 30% blending ratio of Wuhai coal is recommended. [ABSTRACT FROM AUTHOR]

Coal blending models usually take the composition or properties of coal as constraints to optimize the cost of mixed coal for the blending scheme in power plant. Properties of coal are essentially not optimized with this kind of blending model. Therefore, the maximum likelihood quality of design coal of boiler was defined, when the compositions of raw coal can be regarded as random variables. A multi-objective optimization model of coal properties and cost based on chance constraint was established. Pareto fronts of the multi-objective model were presented by genetic algorithm. Analysis of Pareto fronts shows that the optimal data of coal properties and cost are reasonable, and the chance constraints are met well. The blending model can employ the stability of mixed coal as the optimization objective additionally. According to different characteristics of the generator unit and the actual coal to be blended, the optimization model can have different objectives and constraint combinations, which means the good flexibility and practicability.

This work investigated the effect of coal blending on ash fusibility and slurryability of Xinjiang low-rank coal. The results showed that Xinjiang low-rank coals were characterized by high internal water content, high volatile content, high ash fusing point, and poor slurryability, which can not be directly used in coal water slurry gasification. The blending method not only reduced the ash fusibility but also improved the slurryability of these low-rank coals. When the coals with low calcium and high silicon contents (KG and YK) were blended with coal with high calcium content (SH), the ash fusion temperatures of the blended coal were significantly reduced. Moreover, the SH coal showed the worst slurryability performance with a concentration of 48.56%. The slurryability of HS coal can be dramatically improved by blending with KG. When the mass fraction of KG coal reached 70%, the concentration of coal water slurry increased by 11%. For the blended coal of KG and YK, the concentration and stability of coal water slurry gradually increase with the increasing mass ratio of KG. The coal blending method can effectively improve the concentration of coal water slurry for the low-rank coals, which were difficult-to-prepare slurry. [ABSTRACT FROM AUTHOR]

A novel method has been developed to estimate coke reactivity index (CRI) from coal properties through a kinetic approach. The model was derived from mass balance with a kinetic model of batch reactor CRI test. The parameters of kinetic model were optimized using non-linear least squared method. Three main properties of coals, i.e., Fe2O3 content, volatile matter, and coal rank were selected to predict the CRI. The predicted CRI value was in a good agreement with the CRI data. The standard error was less than 5. Coke strength after reaction (CSR) was predicted using linear regression of the CSR and CRI data. The estimated CSR was in good agreement with the CSR data. The sensitivity analysis of coal properties to CRI was also performed using the developed kinetic model. The model was successfully applied for coal blending to predict CRI of the produced coke with standard error 3.7. This model can explain well the catalytic effect of coal and coal blend properties to coke reactivity during the CRI test. [ABSTRACT FROM AUTHOR]

A novel approach to robust optimization of coal blending operations is proposed. While many rigorous mathematical approaches have been developed for this problem in the past, most neglect the uncertainty associated with both the inherent coal quality attributes as well as the sampling and measurement protocols used to measure those attributes. This uncertainty may lead to the imprecise estimation of quality values and force operators to adopt a conservative blend strategy based on safety factors and simple heuristics. One promising approach to rigorously address this shortcoming is through robust optimization (RO), a unique approach to handle data with uncertain and unspecified statistical distributions. In the current work, we first derive a deterministic optimization problem using the premium/penalty structure in typical coal sales contracts. This formulation is then translated to a robust formulation and solved as a Mixed Integer Nonlinear Program (MINLP). A numerical example is presented to demonstrate the utility of the method and to compare the deterministic solution, as the most optimistic and risky blending plan, with the RO solution, as the more pessimistic, yet robust, plan. The proposed strategy can help decision-makers achieve the economic and strategic goals of the operation at acceptable risk levels. [ABSTRACT FROM AUTHOR]

Summary: The substitution of coal blending with sawdust had been widely investigated for metallurgical coke production. In this paper, the physiochemical structures of the semicoke derived from sawdust/coals blends co‐coking were characterized by several analytical techniques including FTIR‐ATR, XPS, NMR, OM, and SEM. Meanwhile, the influence of the sawdust on the physicochemical properties of the sawdust/coals blends were also investigated. Results indicated that partial substitution of coal blending with sawdust benefited from the formation of colloid and optical anisotropy due to the positive synergetic effect, whereas high proportion of sawdust (>10 wt%) inhibited the agglomeration of semi‐coke. On the other hand, the semicoke consisted primarily of aromatic carbons replaced by the oxygen linked to carbons and aliphatic carbons when the coal blending was replaced by high proportion of sawdust, causing a less polyaromatic graphite‐like structure formation in the semicoke. [ABSTRACT FROM AUTHOR]

Abstract Experimental research was carried out on the manufacturing of bio-coal briquettes from a blend of two different types of low-quality coal and biomass waste in the absence of coal carbonization, where the third blend of the material was fermented by adding a bio-activator solution before pressurizing the components into briquettes. The coal samples from Caringin–Garut Regency (BB–Garut) had a low calorific value and a high sulfur content (6.57 wt%), whereas the coal samples from Bayah–Lebak Regency (BB–Bayah) had a higher calorific value and a lower sulfur content (0.51 wt%). The biomass added to the coal blend is in the form of fermented cow dung (Bio–Kohe), and it had a calorific value of 4192 kcal/kg and a total sulfur content of 1.56 wt%. The main objective of this study is to determine the total decrease in the sulfur content in a blend of coal and biomass in which a fermentation process was carried out using a bio-activator for 24 h. The used bio-activator was made from Garant® (1:40) + molasses 1 wt%/vol, and its used amount was 0.2 L/kg. Also, the total sulfur content in the blend was 1.00 wt%–1.14 wt%, which fulfills the necessary quality requirements for non-carbonized bio-coal briquettes. The pyritic and sulfate content in the raw coal was dominant, and the organic sulfur, when fermented with Garant®, was found to be less in the produced bio-coal briquettes by 38%–58%.

Coking coal is essential for the production of steel, and the quality of this coal significantly contributes to the quality of the produced steel. High quality coking coal has low ash content and a range of properties including volatile matter content and predicted coke strength. The coal is improved by processing after it has been mined. This processing varies and coal from multiple sources is blended. This paper introduces an original mixed integer programming model to maximise the profit of coal blending and processing. The model is computationally efficient and can be implemented at any coal mining and processing operation. The multi-period blending model incorporates stockpiling of raw material, and explicitly captures the geological variability of coal using chance constraints. A case study is evaluated and demonstrates that explicitly modelling geological variability can reduce the risk of breaching product specifications without any revenue loss. The improvement is achievable, without additional cost, by selecting the order that coal is fed into a processing plant. [ABSTRACT FROM AUTHOR]

Using low- or zero-carbon fuels is necessary to reduce CO 2 emissions. Gas reburning technology can be applied to existing coal boilers to reduce not only CO 2 but also NO x emissions. In this study, we confirmed the gas reburning effect using lab-scale equipment based on the consumption coal used in real-scale boilers, with the aim of practical application. Bituminous coal was used as the reference fuel, and sub-bituminous coal was blended to determine whether coal blending has an effect on NO x emissions. This was conducted to optimize the coal blending ratio and gas reburning technology for NO x emission reduction and quantify the NO x reduction by the two methods. Blending sub-bituminous coal reduced the unburned carbon (UBC) content, because of its high volatile matter content. Moreover, NO x emissions decreased as the ratio of sub-bituminous coal increased. In terms of the reburning effect, although UBCs increased with the addition of methane, NO x emission decreased by up to 96.05 %. The conversion ratio, defined as the NO x formation ratio of the total fuel N injection, was used to separate the NO x reduction effects of the two methods. Thus, gas reburning in the ammonia co-firing system of coal-fired power plants can significantly reduce NO x emissions. • NO x reduction by coal blending and reburning were described separately using CR. • Methane reburning can dramatically reduce NOx emissions. • Reburning gives insight for NOx reduction during ammonia co-firing plants. [ABSTRACT FROM AUTHOR]

Abstract In order to expand the range of bituminous coal injected into blast furnace, the ash melting behavior and regulation mechanism of bituminous with high calcium and low ash fusion temperature (AFT) were investigated by coal blending. And the mineral transformation behavior in the blended ashes was investigated by X‐ray powder diffractometry with normalized reference intensity ratio software and FactSage software. The experimental results manifest that the softening temperature (ST) of coal D is 8°C lower than that of the hot blast temperature. By adequately mixing coal B and coal D, it is easy to meet the requirements of pulverized coal injection. And coal D has become a standard bituminous for blast furnace injection. However, the high content of CaO in the coal S ash makes the AFT much lower than the hot blast temperature, which leads to the reluctance of the steel industry to inject coal S. With the increase of coal B mass ratio, the content of high‐melting eutectic matters (3Al2O3·2SiO2 and tridymite) increases at high temperature, while the content of low‐melting anorthite, andradite, gehlenite, and grossularite decreases, which leads to the increase of AFTs. The variation in the liquid phase under certain conditions reflects the change in AFT. In summary, by blending with coal B, the ST of blended coals S/B is higher than the hot blast temperature (1250°C), so that coal S can be applied to blast furnace injection. And the injection ratio of coal S in blended coals can reach about 50%.

Copyright of Energy Chemical Industry is the property of Energy Chemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Experimental research was carried out on the manufacturing of bio-coal briquettes from a blend of two different types of low-quality coal and biomass waste in the absence of coal carbonization, where the third blend of the material was fermented by adding a bio-activator solution before pressurizing the components into briquettes. The coal samples from Caringin–Garut Regency (BB–Garut) had a low calorific value and a high sulfur content (6.57 wt%), whereas the coal samples from Bayah–Lebak Regency (BB–Bayah) had a higher calorific value and a lower sulfur content (0.51 wt%). The biomass added to the coal blend is in the form of fermented cow dung (Bio–Kohe), and it had a calorific value of 4192 kcal/kg and a total sulfur content of 1.56 wt%. The main objective of this study is to determine the total decrease in the sulfur content in a blend of coal and biomass in which a fermentation process was carried out using a bio-activator for 24 h. The used bio-activator was made from Garant® (1:40) + molasses 1 wt%/vol, and its used amount was 0.2 L/kg. Also, the total sulfur content in the blend was 1.00 wt%–1.14 wt%, which fulfills the necessary quality requirements for non-carbonized bio-coal briquettes. The pyritic and sulfate content in the raw coal was dominant, and the organic sulfur, when fermented with Garant®, was found to be less in the produced bio-coal briquettes by 38%–58%. [ABSTRACT FROM AUTHOR]

Coal blending is an effective method to reduce the slagging tendency. The mineral transformation within blended coal ashes has an important influence on the slagging behaviors, which have been well studied under conventional air-fuel condition. Oxy-fuel combustion is recognized as one of the most promising CO 2 reduction technologies. However, the mineral transformation within blended coal ashes in oxy-fuel condition has yet to be fully understood. This work is aimed to comprehensively study the influence of CO 2 atmosphere on Ca -containing mineral transformation behaviors during a Ca dominated coal co-firing with a Si/Al dominated coal in O 2 /CO 2 condition by TG-DSC, XRD and HSC simulation. These results show that the atmosphere significantly affects on the transformation of Ca -containing mineral and the final existing form of Ca in the blended coal ashes. When the high content Ca coal is blended with the high content Al/Si coal in the O 2 /CO 2 atmosphere, the CO 2 promotes the transformation of Ca into CaCO 3 and Ca under low temperature mainly exists in the form of CaCO 3 (little CaSO 4) in the blended coal ashes. CaCO 3 under high temperature is decomposed to produce highly active CaO, and CaO reacts with Al/Si to form the low melting point minerals, which may aggravate the slagging tendency. The present study can provide useful information to reduce the slagging behavior of the blended coals in the O 2 /CO 2 atmosphere. • Ca -containing mineral transformation of blended coal oxy-fuel combustion is studied. • The atmosphere affects the final Ca- existing form within blended coal ashes. • The CO 2 in O 2 /CO 2 promotes the transformation of Ca into CaCO 3. • CaCO 3 is decomposed to produce highly active CaO under high temperature. • CaO– Al/Si reaction produces low melting point mineral to aggravate the slagging. [ABSTRACT FROM AUTHOR]

Biomass was used as additives in coal blending for making coke in terms of widening the alternative raw materials and reducing CO 2 emissions. To obtain the influences of biomass incorporation on the semicoke formation, the chemical structure transformation as well as the gas evolution during sawdust (SD)/coal blending (BC) co-coking were investigated using in-situ Fourier transform infrared spectroscopy coupled with mass spectrometry (In-situ FTIR-MS). Meanwhile, the role of biomass in the semicoke formation was also characterized by several analytical techniques. The transformation of the five main functional groups between SD and BC exhibited the largest difference, and the synergistic effect based on the chemical structure transformation was also proposed for the SD/BC blends co-coking. The synergistic effect based on the chemical structure transformation was divided into two stages during semicoke formation. One stage occurred at 100–280 °C that was assigned to the physical effect that inhibited the BC decomposition. Another stage happened at 280–500 °C that was mainly attributed to the hydrogen transfer that enhanced the aromatization of semi-coke. In addition, it was also noted that the thermoplastic properties decreased proportionately to the quantity of the SD, and the non-agglomeration between BC and SD was clearly observed by SEM. ● The co-coking of SD/BC was investigated using In-situ FTIR-MS. ● The differences of chemical structure between SD and BC were observed. ● The synergistic effect during semicoke formation process caused by two stages. ● The thermoplastic properties decreased proportionately to the quantity of the SD. ● The non-agglomeration between BC and SD was clearly observed by SEM. [ABSTRACT FROM AUTHOR]

Many developing countries are opting to rely on coal-fired power mainly due to the abundance of the resource and its economic viability, since the capital needed to build a new coalfired power plant is not as large as a nuclear power plant. Compared to nuclear power, coal-fired power does not bear the risk of major catastrophe and therefore it will be relevant in the power industry for many years to come. However, the major drawback of coal-fired power plant is the fact that it is not a clean energy prospect and it is considered one of the main contributors to the world's greenhouse gases. Coal combustion is usually associated with the emission of greenhouse gases such as CO, CO2, NOx, and SO2. One of the main objectives of coal combustion research is to develop techniques that will help power plant operators to utilize coal cleanly and efficiently by adopting coal blending practices. Currently, emission mitigation and boiler cleanliness issues through coal blending process are focusing more on laboratory scale tests and not utilizing actual plant data and behaviour. This study evaluates the effectiveness of the implementation of Coal Combustion Prediction Analysis Tool (CPAT) as a tool to facilitate power plant operator in predicting the impact of individual or blended coal quality. It will provide early predictions on boiler combustion performance related to the coal quality and it will assist the power plant operators preparing for boiler process control optimization. This study will also discuss slagging and fouling factor of different coal type, which are used in one coal-fired power plant in South East Asia. [ABSTRACT FROM AUTHOR]

India has vast coal resources all over the country; however, the presence of high ash content makes them invulnerable for industrial usage. To compensate for the rapid depletion of high-quality coking coals and to compensate for the demand for coal in iron and steel sectors, coal cleaning or beneficiation and blending techniques have come into limelight for the usage of low-quality coal. In this paper, laboratory-scale experiments were performed on the utilization of Indian high ash non-coking coal (NCC) and imported semi-coking coal (SCC) for the coke preparation. At first, washability characteristics of Indian high ash coal were investigated by using jigging, spiral concentration, and sink and float density separation methods. The optimum cut-off density NCC and SCC coals were blended and sent for the caking properties analysis. Proximate and ultimate analysis, vitrinite reflectance, crucible swelling number, and caking index or roga index have been taken as the measure for the caking ability of coal blends. [ABSTRACT FROM AUTHOR]

The modifications in the low ash fusion temperature (AFT) of Xiangyang coal (XY) were investigated by blending it with three high AFT coals [Jincheng coal (JC), Sunjiahao coal (SJH), and Shajuzi coal (SJZ)], respectively. These three coals all improved XY AFT effectively. With the JC mass ratio varying from 0 to 50%, the AFT of XY/JC gradually increased. The AFT of XY/SJH increased significantly (0–30%), slowly (30–40%), and rapidly (40–50%) with increasing SJH content. For SJZ, the AFT of XY/SJZ increased quickly (0–30%) and very slowly (30–50%). For XY entrained-flow gasification, the appropriate blending ratios of JC, SJH, and SJZ were 40–50%, 30–40%, and 20–40%, respectively. X-ray diffraction, scanning electron microscopy, and FactSage thermodynamic calculation were applied to investigate the effects of mineral transformation on AFT. Quartz (SiO2), anorthite (CaAl2Si2O8), diopside (CaMgSi2O6), and hedenbergite (CaFeSi2O6) were detected in XY ash at 1100 °C. As the mass ratios of high AFT coals increased, the obvious increase in anorthite content led to the rise in the AFT of XY/JC; mullite (Al6Si2O13); and corundum (Al2O3) with a high melt point formed in ashes causing the increase in the AFTs of XY/SJH and XY/SJZ, respectively. [ABSTRACT FROM AUTHOR]

In this paper, the ash fusion temperature (AFT) modification of high calcium Huolinhe lignite (HLH) with the addition of high aluminum Datong coal (DTC) and their corresponding mechanisms were investigated by an AFT tester, X-ray diffractometer, Raman spectrometer, and FactSage software. The AFTs of HLH mixtures increased gradually with the increasing DTC mass ratio due to their corresponding decrease in the total basic oxide content of CaO, MgO, Fe 2 O 3 , Na 2 O, and K 2 O. The formations and content increases of high melting-point minerals (anorthite, cordierite, and mullite), the gradual decrease in the ratios of no bridging-oxide bond/bridging-oxide bond (NBO/BO), and an increase in the R (R = (Q3 + Q2)/(Q1 + Q0)) value resulted in the increases in the AFT and ash viscosity. Considering the variations in the characteristics of AFT and ash viscosity, the 40.0–50.0 % DTC mass ratio might be suitable for HLH entrained-flow bed (EFB) gasification. The combination of AFT measurement and ash viscosity predication using FactSage provided a simple method to determine whether ash characteristics of coal were suitable for EFB gasification. • Huolinhe coal ash fusion temperature (AFT) increased gradually with Datong coal (DTC) addition. • Generations of anorthite and mullite and their content increase caused the increases in the AFTs. • Viscosity-temperature variation of Huolinhe coal mixtures was predicted with adding DTC shares. • The rising R (R = (Q3 + Q2)/(Q1 + Q0)) value resulted in the AFT and ash viscosity increase. [ABSTRACT FROM AUTHOR]

Understanding the sulfur migration during pyrolysis of coals especially high-sulfur coals is important. However, structural complexity and diversity of coals make it face huge challenge. In this study, a predictive model for morphological sulfur migration was developed using machine learning based on proximate analysis, ultimate analysis, sulfur forms of raw coal, ash composition, and blending ratio of coal. Three algorithms, i.e., Random Forest, XGBoost, and LightGBM were introduced and compared. The results show that six features are sufficient to accurately predict the products (R2 > 0.9, RMSE < 3.01%). LightGBM model has the advantages of better accuracy, generalization, efficiency, and performance, and Hyperopt has a higher upper limit than Grid-search. H content has a significant effect on S content in chars (St,d char) and increasing H content from 5.0–5.3 wt% facilitates desulfurization. In addition, CaO, K 2 O and Fe 2 O 3 also have remarkable effects on St,d char. Higher H and volatile contents have a greater effect on thiophene removal in char. This work can provide a new approach to explore the sulfur migration in coal blending for coking. [Display omitted] • Prediction of pyrolytic sulfur migration using Random Forest, XGBoost and LightGBM. • High prediction performance with reduced features (R2 > 0.9, RMSE < 3.01%). • The importance of different features on pyrolytic sulfur form was determined. • LightGBM was used to analyze the influence of sulfur migration from various angles. • Clearer investigation of morphological sulfur migration and new ideas for desulfurization. [ABSTRACT FROM AUTHOR]

The steelmaking industry requires coke as a reducing agent, as an energy source, and for its ability to hold slag in a blast furnace. Coking coal as raw coke material is very limited. Studying the use of biomass as a mixture of coking coal in the synthesis of biocoke is necessary to reduce greenhouse gas coal emissions. This research focuses on biomass and heating temperature through the coal blending method to produce biocoke with optimal mechanical properties for the blast-furnace standard. The heating temperature of biomass to biochar was evaluated at 400, 500, and 600 °C. The blending of coking coal with biochar was in the compositions of 95:5, 85:15, and 75:25 wt.%. A compacting force of 20 MPa was employed to produce biocoke that was 50 mm in diameter and 27 mm thick using a hot cylinder dye. The green sample was heated at 1100 °C for 4 h, followed by quenching with a water medium, resulting in dense samples. Increasing heating temperature is generally directly proportional to an increase in fixed carbon and calorific value. Biocoke that meets several blast-furnace criteria is a coal mixture with coconut-shell charcoal of 85:15 wt.%. Carbonization at 500 °C, yielding fixed carbon, calorific value, and compressive strength, was achieved at 89.02 ± 0.11%; 29.681 ± 0.46 MJ/kg, and 6.53 ± 0.4 MPa, respectively. This product meets several criteria for blast-furnace applications, with CRI 29.8 and CSR 55.1.

In order to expand the range of bituminous coal injected into blast furnace, the ash melting behavior and regulation mechanism of bituminous with high calcium and low ash fusion temperature (AFT) were investigated by coal blending. And the mineral transformation behavior in the blended ashes was investigated by X‐ray powder diffractometry with normalized reference intensity ratio software and FactSage software. The experimental results manifest that the softening temperature (ST) of coal D is 8°C lower than that of the hot blast temperature. By adequately mixing coal B and coal D, it is easy to meet the requirements of pulverized coal injection. And coal D has become a standard bituminous for blast furnace injection. However, the high content of CaO in the coal S ash makes the AFT much lower than the hot blast temperature, which leads to the reluctance of the steel industry to inject coal S. With the increase of coal B mass ratio, the content of high‐melting eutectic matters (3Al2O3·2SiO2 and tridymite) increases at high temperature, while the content of low‐melting anorthite, andradite, gehlenite, and grossularite decreases, which leads to the increase of AFTs. The variation in the liquid phase under certain conditions reflects the change in AFT. In summary, by blending with coal B, the ST of blended coals S/B is higher than the hot blast temperature (1250°C), so that coal S can be applied to blast furnace injection. And the injection ratio of coal S in blended coals can reach about 50%. [ABSTRACT FROM AUTHOR]

The idea of this paper is to properly utilize Indian low-rank coking coal (semi-coking coal) with the blending of high-rank imported coals and to reduce the overall cost of coke making. The blending of the coals has been done in two phases. Effect of blending mass ratio on the swelling index and plasticity parameters has been studied. The effect of maceral content, vitrinite reflectance, and volatile matter content on the caking ability of coals has been studied. Blended sample analysis shows that there is an abrupt drop in the fluidity of the samples compared to the original coals; there is no proper relation between the fluidity and swelling index of the coal blends. Phase 1 coal blends show better results compared to phase 2 samples. Crucible swelling number values for blend 1 and blend 3 from phase 1 are 6 and 4.5, respectively. To validate the swelling number, coke strength after reaction (CSR) and coke reactivity index (CRI) tests have been done for blend 1 and blend 3 coals from phase 1. CSR, CRI for blend 1 and blend 3 samples are 22.18, 71.30 and 23.79, 70.75, respectively. [ABSTRACT FROM AUTHOR]

Due to the continuous improvement of industrial production requirements and green manufacturing demand, manufacturing enterprises and factories need to constantly optimize and improve the system structure. Based on the actual problems in the actual coal blending process, this paper analyzes the reason of the coal blending error in coal blending process and the optimization scheme of intelligent control of coal blending process. We optimized the overall structure of the coal blending system, improved the coal blending system which use the fuzzy control system. At the same time, we used MATLAB to simulate and analyse the simulation results. This paper gives an illustration to the optimal structure and system of the coal blending system, effectively improves the accuracy and stability of the coal blending process control system, reduces the coal blending error and improves the quality of coal blending in general. [ABSTRACT FROM AUTHOR]

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hardgrove Grindability Index (HGI) is a determining factor of energy consumption during grinding. The current study is aimed at investigating the influence of the blending behavior on HGIs of two dissimilar coal samples. In this study, one local coal sample is taken from Lakhra coal deposits and second sample is extracted from Indonesian coal reserves for empirical experiment and analysis. The total number of nine blends with different blending ratios based on the Net Calorific Value (NCV) was made. In addition, the samples were further tested for proximate and ultimate analysis, Gross Calorific Values and HGI respectively. The ASTM D409-D409M standard Hardgrove grindability tester was used for the determination of HGI of cited two coal samples. The main purpose of this study is to determine the blends that specify the optimum results those are appropriate for power sectors and cement industries. According to the above study, the blend no 2 and 3 demonstrate the optimum results for cement factories with approximately HGI 46 and 49 with sulphur content 1.01 and 1.17, whereas blend no 4 and 5 are appropriate for power sectors with approximately HGI 52 and 54 with sulphur content 1.37 and 1.58. Furthermore, the value of the blends for HGI and moisture content shows the inverse relation, as the moisture content increases HGI value decreases. Similarly, research results also determine that there is also inverse relationship between the blend value of volatile matter and total carbon with HGI. Additionally, the GCV also exhibits inverse relationship while ash and fixed carbon reveal direct relationship with the value of blends for HGI. In the same manner, sulfur also exhibits direct relation with HGI value.. [ABSTRACT FROM AUTHOR]

Abstract In this work a decision making framework for the design of the flue gas treatment section of a power plant has been developed, including particle, NOx and SO 2 removal operations. It has been applied to a coal based thermal power plant in Spain to select the optimal technologies and its sequence. Surrogate models for the treatments have been developed. The problem corresponds to a mixed integer non-linear programming one including catalytic and non-catalytic NOx removal, allowing various allocations for the catalytic technology, electrostatic precipitation and wet or dry SO 2 removal. It is reformulated as a non-linear problem to evaluate bypass opportunities. The optimization suggests the use of electrostatic precipitation, followed by catalytic NOx removal and dry SO 2 removal. Next, a coal blending problem has also been solved for two objective functions. When only treatment costs are considered, the use of imported coal is recommended, but an increase of 4% in its price can change the decision into the use of national coal. If the energy within the coal is added to the objective function, crude tar coal is included in the blend and imported coal is used to maintain the emissions within limits. Limestone Forced Oxidation is the selected technology. Highlights • Heuristics and mathematical optimization are used to select gas treatment. • Ash, catalytic NOx and dry SO2 removal are the selected technologies in this order. • Only imported coal is suggested if only treatment is analyzed. • Crude tar coal is added to the blend when power produced is included in the objective. • Limestone Forced Oxidation is a more flexible technology to process coal blends. [ABSTRACT FROM AUTHOR]

Hardgrove Grindability Index (HGI) is a determining factor of energy consumption during grinding. The current study is aimed at investigating the influence of the blending behavior on HGIs of two dissimilar coal samples. In this study, one local coal sample is taken from Lakhra coal deposits and second sample is extracted from Indonesian coal reserves for empirical experiment and analysis. The total number of nine blends with different blending ratios based on the Net Calorific Value (NCV) was made. In addition, the samples were further tested for proximate and ultimate analysis, Gross Calorific Values and HGI respectively. The ASTM D409-D409M standard Hardgrove grindability tester was used for the determination of HGI of cited two coal samples. The main purpose of this study is to determine the blends that specify the optimum results those are appropriate for power sectors and cement industries. According to the above study, the blend no 2 and 3 demonstrate the optimum results for cement factories with approximately HGI 46 and 49 with sulphur content 1.01 and 1.17, whereas blend no 4 and 5 are appropriate for power sectors with approximately HGI 52 and 54 with sulphur content 1.37 and 1.58. Furthermore, the value of the blends for HGI and moisture content shows the inverse relation, as the moisture content increases HGI value decreases. Similarly, research results also determine that there is also inverse relationship between the blend value of volatile matter and total carbon with HGI. Additionally, the GCV also exhibits inverse relationship while ash and fixed carbon reveal direct relationship with the value of blends for HGI. In the same manner, sulfur also exhibits direct relation with HGI value. [ABSTRACT FROM AUTHOR]

Coal blending is an effective way to organize and control coal ash fusibility to meet different requirements of Coal-fired power plants. This study investigates three different eutectic processes and explains the mechanism of how coal blending affects ash fusibility. The blended ashes were prepared by hand-mixing two raw coal ashes at five blending ratios, G:D = 10:90 (G10D90), G:D= 20:80 (G20D80), G:D = 30:70 (G30D70), G:D = 40:60 (G40D60), and G:D = 50:50 (G50D50). The samples were heated at 900 °C, 1000 °C, 1100 °C, 1200 °C, and 1300 °C in reducing atmosphere. XRD and SEM/EDX were used to identify mineral transformations and eutectic processes. The eutectic processes were finally simulated with FactSage. Results show that the fusion temperatures of the blended ashes initially decrease and then increase with the blending ratio, a trend that is typical of eutectic melting. Eutectic phenomena are observed in D100, G10D90, and G30D70 in different degrees, which do not appear in G100 and G50D50 for the lack of eutectic reactants. The main eutectic reactants are gehlenite, magnetite, merwinite, and diopside. The FactSage simulation results show that the content discrepancy of merwinite and diopside in the ashes causes the inconsistent eutectic temperatures and eutectic degrees, in turn decrease the fusion temperature of the blended ash and then increase them with the blending ratio.

Based on this study, the Al2O3 content of Jungar coal ash is over 45%, and the resistivity of high-Al2O3 ash in Jungar reaches up to 1012 Ω​·cm. These results seriously influenced the electric characteristics of fly ash, and the collection efficiency of electrostatic precipitators (ESPs) evidently decreased. To facilitate the effective collection of fine particle in the flue gas generated before and after coal blending via ESP, the fly ash obtained from a power plant electrostatic precipitation was analyzed in terms of resistivity, size distribution, and cohesive force through a portable dust electrical resistivity test instrument, Bahco centrifuge, and a cohesive force test apparatus invented by the researchers. The mixed ratio of else coal is higher than 50%, the resistivity of the fly ash in the flue gas was lowered to approximately two orders of magnitude, and the size distribution showed an evident decrease in the PM2.5 and PM10 content in fly ash. In addition, the adhesive force and efficiency increase from 95.9 to 99.5% in the electrostatic precipitation. Therefore, the combustion of blending coal is an effective approach to improve the efficiency of ESP used to collect high-Al2O3 fly ash. [ABSTRACT FROM AUTHOR]

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The low ash and high iron content of Victorian brown coal (VBC) makes it difficult to achieve desirable slagging for entrained-flow gasification. This study investigates the blending of VBC char with a high-ash bituminous coal for entrained-flow gasification. An industrially pyrolyised VBC char, a silica-rich bituminous coal char (BCC), and VBC char with BCC blends in three different blending ratios (20%BCC, 40%BCC and 80%BCC) are selected for high temperature gasification investigation in a lab-scale drop tube furnace (DTF) for temperatures ranging from 1000 to 1300 °C with different CO 2 volume fractions. Scanning electron microscopy (SEM) coupled with elemental mapping, advanced synchrotron XANES and Mössbauer spectroscopy (MS) are employed to clarify the slagging propensity and iron transition behaviours during the blend co-gasification. It is found that VBC char, even in large sized particles, achieves a high char conversion and more than 50% CO fraction in syngas at 1300 °C, while BCC shows a lower char conversion and only 15% CO fraction in the same condition, due to only small particles being consumed. The blending of BCC into VBC lowers the char conversion compared to that of VBC alone due to the ash interactions. However, the element (Fe/Ca/Mg) loss during gasification reduces remarkably upon the addition of BCC, showing that the silica from BCC captures these elements. In addition, VBC generates more than 20% metallic iron out of total Fe-species during gasification, and the amount increases when temperature increases, which is undesirable for slag discharge. In contrast, blending 20% BCC with VBC char reduces α-Fe from 15% to about 7%, and reduces Fe 3 O 4 from 12% to less than 6%. This is because the silica in BCC can preferentially capture the iron-bearing compounds before they are reduced into metallic iron. Additionally, the unreacted carbon is covered by the slag, stopping it from reducing the Fe 2+ to metallic iron Fe 0 . The reduction of metallic iron is closely linked to the increase on the ash slagging extent, which is beneficial to slag discharge in entrained-flow gasifiers. [ABSTRACT FROM AUTHOR]

Petroleum coke (petcoke), especially high vanadium (V) petcoke, has been produced increasingly because of the growing consumption of petroleum oil. Petcoke ash fusibility is closely related to ash slagging, which has an important impact on the clean and efficient utilization of petcoke. This study investigates a high V petcoke ash fusibility and its modification by coal blending and flux addition at reducing atmosphere. X-ray diffraction (XRD) and scanning electronic microscopy (SEM) were used to determine the crystalline minerals and surface morphology of high-temperature ash slag, respectively. The ash fusion process was predicted by thermodynamic equilibrium calculations. The results show that Shengli Oilfield petcoke (SL) has a high ash fusion temperature (AFT), whereas coal blending and flux addition can effectively decrease the AFT of SL, which may be ascribed to the mineral transformations during ash fusion process. The synergistic effects of high-melting vanadium trioxide (V 2 O 3 ) and coulsonite (FeV 2 O 4 ) result in the high AFT of SL. When SL blends with Shenmu (SM) coal and Qi coal (QC), the formation of low-melting andradite (Ca 3 Fe 2 Si 3 O 12 ) and the decrease of V 2 O 3 contribute to the progressive decline of AFT. When the addition of flux calcium oxide (CaO) reaches 10%, the low-melting calcium orthovanadate (Ca 3 V 2 O 8 ) formed under reducing atmosphere decreases the AFT. With increasing CaO content, the content of V 2 O 3 and FeV 2 O 4 decreases while that of Ca 3 V 2 O 8 and Ca 3 Fe 2 Si 3 O 12 increases gradually, which further leads to a decrease in the AFT. [ABSTRACT FROM AUTHOR]